Filter



Nov. 26, 1935. w-. CHAPMAN 2,022,403

FILTER Original Filed Sept. 50, 1931 4 Sheets-Sheet l &

Nov. 26,- 11935. w. L. CHAPMAN 2,022,403

FILTER Original Filed Sept. 50, 1931 4 Sheets-Sheet 2 FILTER OriginalFiled Sept. 30, 1931 4 Sheets-Sheet 5 Nov. 26, 1935. w. L. cHAMAN FILTEROriginal Filed Sept. :50, 1951 4 Sheets-Sheet 4 Patented Nov. 26, 1935UNE'EED STATE? PATENT QFFEQE FILTER Application September 30, 1931,Serial No. 565,962 Renewed October 11, 1935 5 Claims.

'l l'he present invention relates generally to filters. Moreparticularly the invention relates to that type of filter which is knownas a rotary leaf pressure filter and comprises (1) a horizontallyextending, substantially cylindrical casing which consists of an uppersemi-cylindrical section and a complemental lower, semi-cylindricalsection and has a longitudinal series of inspection doors in the uppersection thereof and an inlet for the material to be filtered and a10ngitudinal trough in its lower section; (2) a hollow shaft whichextends through and is journalled in bearings at the ends of the casingand. is driven at a comparatively low speed during the filteringoperation; (3) a series of filter leaves which are mounted fixedly onthe hollow shaft and. are constructed to supply the filtrate to theinterior of the shaft for discharge from the casing; (4) a spray pipewhich is disposed in the top part of the upper section of the casing andembodies jet openings in the lower portion thereof whereby steam orcompressed air may be jetted against the sides of the filter leaves tobreak up and remove the cakes which form and accumulate on the leavesdurng operation of the filter; and (5) a spiral conveyor which ismounted in the trough in the lower section of the casing and serves,during cleaning of the filter, to discharge through an opening in thelower casing-section the cake pieces which are removed from the filterleaves by the spray pipe.

One object of the invention is to provide a filter of the aforementionedtype in which discharge of the cake from the casing is expedited byvirtue of the fact that the trough for the spiral conve c-r is locatedat one side of the extreme bottom portion of the lower casing-sectionand is so positioned that during removal of the cakes from the leaves bythe jets of steamer compressed air from the spray pipes, the cake piecesare forced therein by the leaves in response to drive of the hollowshaft.

Another object of the invention is to provide a filter of the rotaryleaf pressure type in which the spray pipe for use in effecting removalof the cakes from the side faces of the leaf filters is located at oneside of the extreme top part of the upper casing-section and ispositioned directly adjacent to the inspection doors so that the jetopenings therein may be readily cleaned without the necessity ofremoving the pipe from the casing.

A further object of the invention is to provide a filter of the rotaryleaf type which is generally of new and improved construction, may bemanufactured at a reasonable cost and is capable of withstanding greaterinternal pressure than previously designed filters of the same generalcharacter.

Other objects of the invention and the various 5 advantages andcharacteristics of the present filter construction will be apparent froma consideration of the following detailed description.

The invention consists in the several novel features which arehereinafter set forth and are 10 more particularly defined by claims atthe conclusion hereof.

In the drawings which accompany and form a part of this specification ordisclosure and in which like numerals of reference denote corre- 15sponding parts throughout the several views:

Fig. l is a View, partly in side elevation and partly in verticallongitudinal section, of a filter embodying the invention;

Fig. 2 is a view of one end of the filter; 20

Fig. 3 is a view of the other end of the filter, exhibiting in detailthe construction and arrangement of the gearing for driving the hollowshaft for the filter leaves and the spiral conveyor for discharging thecake pieces from the casing; 25

Fig. 4 is a vertical transverse section on the line 4--4 of Fig. 1;

5 is a vertical longitudinal section showing the construction of thecasing of the filter;

Fig. 6 is a detail of the gearing for driving the 30 hollow shaft andthe spiral conveyor; and

Fig. 7 a section on the line 1-4 of Fig. 6.

The filter which forms the subject matter of the invention is designedto filter any kind of material in liquid or semi-liquid form andcomprises 35 a horizontally extending, substantially cylindrical casingIt), a hollow shaft H and a set of leaf filters l2 on the shaft. Thehollow shaft H extends through and lengthwise of the casing and isdriven as hereinafter described so as to rotate the filter leaves duringoperation of the filter. The filter leaves l2 are mounted in spacedrelation on the shaft and are arranged so that the material to befiltered passes therethrough for filtering purposes and the filtrate issupplied to the interior of the shaft for discharge from the casing.

The casing iii-is designed to withstand a comparatively high pressureand consists of a semicylindrieal upper section i3 and a complemental 50lower, semi-cylindrical section it. The upper section it is fabricatedfrom steel plate and consists of a curved or half round side wall !5 anda pair of semi-circular end walls is and H. The end walls are welded tothe end margins of 55 the side wall 55 and are dished or bowed outwardlyso that the upper casing-section as a Whole, is extremely ,rigid and iswell adapted to withstand comparatively great internal pressure. A pairof longitudinally extending slots l8 and 18 are formed in the side walll5. The slot I3 is located at one side of the extreme top part of theside wall 15 and extends from the end wall it to the end wall IT, Theslot I9 is slightly wider than the slot i8 and also extends from the endwall it to the end wall ll. It is disposed directly beneath and isparallel to the opening l8 and forms an opening whereby access may behad to the interior of the casing. A fabricated frame 26 is associatedwith the slot l9. This frame supports a plurality of inspection doors 2|and consists of a pair of steel side bars 22 and 23 and a pair of steelend bars 24. The side bars are welded or otherwise secured to theportions of the side wall of the upper casing-section which define theside edges of the opening 19. The end bars are welded or otherwisesecured to the end walls of the upper casing-section and operate,together with cross pieces 25 to hold the side bars in laterally spacedrelation. The cross pieces 25 extend between the side bars and tend tostrengthen or reinforce the frame 29. The inspection doors 2| aredisposed endto end and operate when in their closed position, to' coverthe frame 28 and thus to close the slot 19. They are connected pivotallyto links 26. The latter extend -circumferentially with respect to thecasing and are connected pivotally by pins 21 to pairs of ears 28 whichare formed integrally with and project outwardly from the side bar 23 ofthe frame 28. The distal ends of the links 26 are slotted so as toreceive bolts 30 which are connected pivotally by pins 3| to pairs ofears 32. Nuts 33 are mounted on the distal ends of the bolts 38 andoperate, when tightened, to swing thelinks 28 inwardly so as to clampthe inspection doors 2! in their closed position. The pairs of ears 32are formed integrally with the side bar 22 of the cast steel frame 20and are extended so as to form portions 32*- which overhang the slot I 8and are welded to the portion of the side wall 15 of the uppercasing-section which defines the upper side margin of the slot 4 8. Astrip 34 serves to close the slot l8. This strip is semi-cylindrical inconformation and forms a spray pipe compartment 34 Said strip 34 fitsand is secured in semi'cylindrical recesses 32 in the extended portions32* of the ears 32, and is arranged so that one of the side edgesthereof abuts against the side bar 22 of the frame 213 and its otherside edge abuts against the portion of the side wall l5 which definesthe upper side edge of the slot I 8. By forming the ears 32 so that theyoverhang the slot I8, the strip 84 is securely held againstdisplacement.

The lower section (4 of the casing I is fabricated from steel plate andcomprises a curved or half round side wall 35 and a pair of semicircularend walls 36 and 31. The side wall 35 is arranged so that the sidemargins thereof abut against the side margins of the side wall l of theupper casing-section [3. The end walls 36 and 3'! are joined in anysuitable manner to the end margins of the side wall 35. The end wall 36is associated with the end wall it of the upper casing-section l3 andhas the upper edge thereof arrangcd so that it abuts against the loweredge of said end wall I6. The end wall 3? is associated with the endwall ll of the upper section of the casing and has the upper edgethereof arsteel.

ranged in abutting relation with respect to the lower edge of the endwall H. The side wall 35 has formed in the lower portion thereof alongitudinally extending opening 38. The latter is arranged so that themajor portion thereof is located at on side of the extreme bottomportion of the lower casing-section l4, and is positioned substantiallydiametrically opposite the slots l8 and Hi. It extends from the end wall36 to the end wall 3'! and forms the entrance to a longitudinallyextending trough 39. The latter is defined by a pair of steel sideplates 45 and M and a bottom plate 42, The bottom plate 42, like theside plates 46 and M, is formed of It is curved so that it issubstantially l5 semi-cylindrical in conformation and forms the bottomof the trough 39. The side plate 65 extends substantially vertically andis welded at the bottom margin thereof to one of the side margins of thebottom plate 12. It forms one side of the trough 39 and is welded at itsupper margin to the side wall 35 of the lower casingseetion. The sideplate 4| forms the other side of the trough 39 and extends between andis welded to the other side margin of the bottom plate 42 and the sidewall 35. The side plates at and 4| are preferably arranged so that theyare upwardly divergent and form a flared mouth or entrance way for thetrough. The ends of the trough are closed by means of a pair of endpieces 43. The latter are in the nature of'extensions of the side wallsof the lower casingsection and are welded to the end edges of the sideplates 4'. and 4! and the bottom plates 42.

To strengthen the plates 40, 4| and 42, a unitary structure 44 isprovided. This structure is formed of steel and comprises a series ofU-shaped ribs 45 and cross ribs d5. The U-shaped ribs 45 extend aroundand are Welded or otherwise secured to the plates 40, Al and 42 and havethe upper ends thereof connected to the side wall 35 of the lowercasing-section. The cross ribs extend between and space apart the ribs45. They are formed integrally with the ribs 45 and underlie the extremelower portion of the bottom plate 45 42, as clearly indicated in Fig. 4of the drawings. The upper and lower sections of the casing are held inclamped relation by a set of. swing bolts 4'! at one side of the casingand a set of swing bolts 48 at the other side of the casing. The bolts41 are formed of forged steel and are connected pivotally to a rod 49which is carried in aligned openings 58 in a set of lugs 5|. The lugs 5|are welded to the side wall 35 of the lower casing-section [4 and arearranged so that they alternate with the swing bolts 4'1, and theopenings 50 are disposed directly beneath and in vertical alignment withthe adjoining side margin of the side wall 35 of the casing-section M.The distal ends of the swing bolts 47 are shaped to form externallythreaded stems 47 These stems carry clamp nuts N and fit between lugs 52on plates 53. The plates 53 are preferably formed of steel castings andare secured in any suitable manner to the portion of the side wall iiiof the upper casingsection that is directly above the lugs 5|. The lugs52 project outwardly from and are formed integrally with the plates andhave flattened upper portions against which abut the nuts 41 When thenuts 41 are tightened, the bolts 41 operate to hold the casing sectionsin clamped relation. The central or intermediate portions of the swingbolts 4'! are curved conformably to the casing and are constructed sothat when they are in their operative position, the externally threadedstems 97 are positioned in vertical alignment with the rod 49 and thecontiguous abutting edges of the casing-sections l3 and I4. As a resultof this arrangement, the casing is adapted to withstand exceedinglygreat internal pressure inasmuch as the clamping pressure of the swingbolts 41 is applied through the contiguous meeting side margins of thecasing-sections and the lines of force of the bolts coincide with thelines of force tending to spread the sections apart. The lugs 52 arearranged so that the flattened upper portions thereof are disposeddirectly above and in vertical alignment with the pivot rod 49. Theswing bolts 98 are located diametrically opposite the swing r bolts 4'!and are pivotally mounted on a rod 54.

This rod is carried by a set of lugs 55 which are welded to the sidewall of. the lower casing-section Hi. The central portions of the swingbolts 48 are curved conformably to the periphery of the casing similarlyto the central portions of the swing bolts 4?. The upper ends of theswing bolts 48 embody externally threaded stems which carry clamp nuts56. The latter cooperate with a plurality of lugs 51 on plates 58 toeffect a clamping connection between the two casing-sections. The plates58 and the lugs 51 correspond respectively with the plates 53 and thelugs 52. The abutting edges of the walls l5 and 36 of thecasing-sections are clamped together by bolts 59.

The latter extend through bars 68 which are welded to and project otwardly from the aforesaid abutting margins of the end walls [6 and 3B.The abutting edges of the end walls l1 and 31 of the casing-sections areclamped together by bolts 6| which extend through bars on said end wallsI! and 31.

The casing i0 is supported by means of a pair of legs 52 and a pair oflegs 63. The legs 62 support one end of the casing and are bolted orotherwise secured to a bracket structure 54 which is attached to the endwall 36 of the lower casingsection it. The legs 63 support the other endof the casing and are secured to a bracket structure 65 which isattached to the end wall 31 of the casing-section l 4.

The material to be filtered is introduced into the casing by way of aplurality of flanged pipe connections 66. These connections are locatedbetween the ribs of the unitary reinforcing structure 49, are welded tothe side plate 6! and communicate with the trough in the lowercasingsection i l by way of openings 57 in the aforesaid side plate M.An outlet connection 69 for use during cleaning of the filter isconnected to the bottom plate 42. This connection is located at thecentral part of the casing, is closed by a plate or valve during normaloperation of the filter and communicates with the trough via an openingin the central portion of the bottom plate 42.

The hollow shaft H which supports the filter leaves !2 has one endthereof connected to a pipe element l9 and is provided at its other endwith a spindle H. The nine element 59 forms an outlet for the filtrate.extends through a packing box 22 and is journalled in a bearing E3. Thepacking box 72 comprises a cylindrically shaped split casting M of steeland a follower 15. The split casting is secured in a circular opening'59 in the meeting or abutting margins of the end walls i5 and 3 5 of.the casing sections l8 and i4 and forms a bearing for the inner end ofthe pipe element. The follower i5 is slidably mounted on the pipeelement and serves to clamp an annular band i? of packing materialaround the pipe ele ment so as to prevent leakage of the material to befiltered through the end of the casing embodying the end walls 5 and 35.The bearing l3 surrounds the outer end of the pipe element and embodiesa supporting arm 18 which is fixedly secured to and projects outwardlyfrom the bracket structure 64. The spindle H is solid so as to close thecontiguous end of the hollow shaft. It it journalled in a bearing 19.The latter is in the nature of. a packin box and comprises acylindrically shaped split casting 88 of steel and a follower 8!. Thesplit casting is secured in a circular opening 82 in the meeting orabutting margins of the end walls I! and 31. The follower 8| is mountedaround the central portion of the spindle and fits slidably in thecasting 89. It is held in place by bolts 83 and operates to clamp anannuar strip 84 of clamping material around the spindle so as to preventleakage of the material to be filtered through the end of the casingembodying the end walls I! and 31.

The hollow shaft II is driven by an electric motor 85 so as to rotatethe filter leaves l2. The motor 85 is mounted on a bracket 85 on one ofthe legs 62 and drives the shaft through the medium of speed reducinggearing. The latter is mounted in a cast metal housing 81 on the bracketstructure and comprises a horizontally extending shaft 88 which extendsthrough and is journalled in the central portion of the housing and isconnected to the armature shaft of the motor by a coupling 89; a worm 98which is formed integrally with the portion of the shaft 88 that isdisposed within the housing; a worm wheel 9| which is fixed to ahorizontally extending shaft 92 and meshes with and is driven by theworm 99; a pinion 93 which is fixed to the shaft 92 and meshes with anddrives a gear wheel 94; a shaft 95 which is' located above the shaft 88and has keyed thereto the gear wheel 94; a pinion 96 which is disposedoutside of the casing and is fixedly secured to one end of the shaft 95;and a gear wheel 97 which meshes with and is driven by the pinion 96 andis keyed or otherwise secured to the outer end of the spindle H. Thehousing 81 is designed to contain oil so that the various parts of thegearing disposed therein are at all times properly lubricated. The shaft92 is located beneath the worm shaft 88 and is journalled in bearings 98in the walls of the housing.

The filter leaves l2 are circular and embody laterally spaced, screencovered, foraminous side walls l2 In addition to the side walls, thefilter leaves embody enlarged hubs I 2 which are fixedly secured to thehollow shaft H and embody n ducts which register with apertures (notshown) serve in conjunction with the hubs I2, to hold the leaves inspaced relation. They also serve to scrape the inner periphery of thecasing [0 so as to keep the latter clean and prevent the accumulation ofsediment.

In order to free the filter leaves from the cakes which accumulate onthe side walls thereof, a spray pipe I08 is provided. This spray pipeextends longitudinally of the casing and is disposed in the compartment34*. One end of the pipe extends through a packing or stuffing box H3!in the end wall iii of the upper casing-section 13 and is connected toreceive steam or compressed air. The other end of the pipe is closed bya cap Hill and has a plate lilll welded thereto. Bolts I extend throughthe plate I00 and into a plate I00 which is in the nature of a stufiingbox and is secured on the end wall I! of the upper casing section. Bymanipulating the bolts I00 the pipe may be adjusted longitudinally. Theportion of the spray pipe within the casing embodies downwardlyextending jet openings I02. These openings are arranged so as to causejets of steam or air under pressure to impinge directly against thecakes on the filter leaves in order to cause them to dry and fall inpieces to the bottom of the casing. By arranging the spray pipe withinthe compartment 34 which is next to the inspection doors 2I, cleaning ofthe jets may be readily effected through the slot I9 without removingthe pipe from its operative position During normal operation of thefilter, the supply of steam or compressed air to the pipe is cut off.When the cakeformation on the filter leaves becomes too thick and it isdesired to clean the casing, the supply of material to be filtered tothe casing is cut off and the material within the casing is drained byway of the outlet connection 59. After drainage of the material from thecasing, steam or compressed air is supplied to the pipe I00 and isjetted downwardly by the jet openings I02 against the sides of thefilter plates with the result that the cakes on the filter plates aredried. and fall to the bottom of the casing.

The cake pieces which accumulate on the bottom of the casing duringcleaning of the filter fall into the trough 39 and are conveyed to theoutlet connection 69 for discharge purposes by means of a spiralconveyor I03. This conveyor comprises a shaft I04, a right hand spiralplate I and a left hand spiral plate I 06. The shaft I04 extendslongitudinally of the trough and has the ends thereof mounted in packingboxes I01 in the end pieces 43. The right hand spiral plate I05 and theleft hand spiral plate I06 are secured to opposite ends of the shaft I04and operate, during drive of the shaft to feed the cake pieces into theoutlet connection 69. Drive of the conveyor is effected through themedium of a clutch I08 which consists of a pair of clutch members I09and H0. The clutch member I09 is mounted on one end of, and is driven bythe shaft 92 of the gearing for driving the hollow shaft II from theelectric motor 85. The clutch member 0 is slidably mounted on one end ofthe conveyor shaft I04 and operates, when shifted into mesh with themember I08, to effect a driving connection between the conveyor and theelectric motor. By connecting the spiral conveyor so that it is drivenby the gearing for the hollow shaft 1 I, the motor 85 serves to driveboth the hollow shaft and the spiral conveyor. When the clutch for thespiral conveyor'is shifted into its operative position, the motor drivesconjointly the hollow shaft and the spiral conveyor and the filterleaves are rotated so that the cake formation on the side walls thereofare rotated into contact with the jets of steam or compressed airemanating from the spray pipe I00. During cleaning of the filter, thecake pieces after being loosened from the sides of the filter leaves,fall to the bottom of the casing, as previously pointed out. By virtueof the fact that the leaves are rotated during the cleaning operation,the pieces, instead of accumulating directly on the bottom, accumulateat one side. The trough 39 for the spiral conveyor is located at oneside of the extreme bottom of the lower casing-section I4 so that it isdirectly beneath the place at which the cake pieces are rotated by thefilter leaves. As a result of this arrangement, the cake pieces dropdirectly into the trough and are quickly removed from the casing by thespiral conveyor.

The herein disclosed filter may be manufactured at a comparatively lowcost and is capable of being used in connection with material undercomparatively high pressure by reason of the fact that the casingthereof is fabricated from pieces or parts of steel and the bolts whichare used to hold the sections of t e casing in clamped relation areconstructed and formed so as to apply the clamping pressure directlythrough the abutting margins or edges of the sections. By reason of thefact that the trough for the spiral conveyor is located at one side ofthe extreme bottom part of the lower casing-section, removal of the cakepieces from the casing is greatly facilitated and expedited duringcleaning of the filter.

The invention is not to be understood as restricted to the details setforth, since these may be modified within the scope of the appendedclaims, without departing from the spirit and scope of the invention.

Having thus described the invention, what I claim as new and desire tosecure by Letters Patent, is:

1. In a batch type filter of the character described, the combination ofa substantially cylindrical, horizontally extending casing provided withan inlet for receiving under pressure the material to be filtered, meansat the bottom of the casing forming a dependirr trough extend ing fromone end of the casing to the other and arranged so that the majorportion thereof is located at one side of the extreme bottom point ofthe casing, a normally closed outlet for the trough, a hollow elementextending longitudinally of the casing and supported for rotation at theends of the casing, a plurality of laterally spaced filter leavessecured fixedly to the element and connected to supply the filtrate tothe interior of said element for discharge from the casing, meansadapted to be operated during cleaning of the filter for removing andloosening the cake formation from the sides of the filter leaves, meansfor driving the element in such direction as to cause the filter leavesto revolve through the material during normal use of the filter and toforce the loosened cake pieces downwardly and then substantiallyhorizontally across the extreme bottom of the casing in the direction ofthe trough, and then into said trough during cleaning of the filter, anda spiral conveyor disposed in the trough and operative during drivethereof and after opening of the outlet to discharge the cake piecesfrom the trough through said outlet.

2. In a filter of the character described, the combination of asubstantially cylindrical horizontally extending casing provided with aninlet for receiving under pressure the material to be filtered andembodying in the top portion thereof andat one side of its extreme toppoint a longitudinal series of inspection openings, a plurality of doorsfor closing the inspection openings, a hollow element extendinglongitudinally of the casing and supported for rotation at the ends ofthe casing, a plurality of laterally spaced filter leaves securedfixedly to the element and connected to supply the filtrate to theinterior of said element for discharge from the casing, a

longitudinally extending spray pipe connected to receive fluid underpressure and disposed in the top portion of the casing at said one sideof the top point and positioned immediately above and in substantiallycontacting relation with the inspection openings so that it isaccessible from the outside of the casing by way of said openings, saidpipe having jet openings for spraying the fluid against the sides of thefilter leaves and be ing adapted to be used in cleaning the filter toremove and loosen the cake formation from the sides of the filterleaves, means for driving the element so as to cause the filter leavesto revolve through the material during normal use of the filter and tobring successive portions of the cake formation into range of the jetsof fluid under pressure from the spray pipe during cleaning of thefilter, and means associated with the bottom of the casing fordischarging the cake pieces from the casing.

3. In a filter of the character described, the combination of asubstantially cylindrical horizontally extending casing provided with aninlet for receiving under pressure the material to be filtered andembodying in the top portion thereof a pair of substantially parallelslots, a frame secured to the casing. over one of the slots and formingwith said one slot a series of inspection openings, doors for closingthe inspection openings, a member associated with and attached to theframe and shaped to close and form a longitudinal compartment over theother slot, a hollow element extending longitudinally of the casing andsupported for rotation at the ends of the casing, a plurality oflaterally spaced filter leaves secured fixedly to the element andconnected to supply the filtrate to the interior of the element fordischarge from the casing, a longitudinally extending spray pipeconnected to receive fluid under pressure and disposed in the aforesaidcompartment in such a manner that it is accessible from the outside ofthe casing by way of the inspection openings, said pipe having. jetopenings for spraying the fluid against the sides of the filter leavesand being adapted to be used in cleaning the filter to remove and loosenthe cake formation from the sides of the filter leaves, means fordriving the element so as to cause the filter leaves to revolve throughthe material during normal use of the filter and to bring successiveportions of the cake formation into range of the jets of fluid underpressure from the spray pipe during cleaning of the filter, and meansassociated with the bottom of the casing for discharging the cake piecesfrom the casing.

i. In a filter of the character described, the combination of asubstantially cylindrical horizontally extending casing provided with aninlet for receiving under pressure the material to be filtered andembodying in the top portion thereof a pair of substantially parallelslots, a frame secured to the casing over one of the slots and formingwith said one slot a series of inspection openings, ears attached to theframe and extending over the other slot, doors connected to the ears andarranged to close the inspection openings, a member secured to said earsand shaped to close and form a longitudinal compartment over said otherslot, a hollow element extending longitudinally of the casing andsupported for rotation at the ends of the casing, a plurality oflaterally spaced filter leaves secured fixedly to the element andconnected to supply the filtrate to the interior of said element fordischarge from the casing, a longitudinally extending spray pipeconnected to receive fluid under pressure and disposed in the aforesaidcompartment in such a manner that it is accessible from the outside ofthe casing by way of the inspection openings, said pipe having jetopenings for spraying the fluid against the sides of the filter leavesand being adapted to be used in cleaning the filter to remove and loosenthe cake formaltion from the sides of the filter leaves, means fordriving the element so as to cause the filter leaves to revolve throughthe material during. normal use of the filter and to bring successiveportions of the cake formation into range of the jets of fluid underpressure from the spray pipe during cleaning of the filter, and means 3%,associated with the bottom of the casing for.

discharging the cake pieces from the casing.

5. In a filter of the character described, the combination of asubstantially cylindrical horizontally extending casing provided with aninlet for receiving under pressure the material to be filtered andembodying in the upper portion thereof a longitudinal series ofinspection openings, a plurality of doors for closing. the inspectionopenings, a hollow element extending longitudinally of the casing andsupported for rotation at the ends of the casing, a plurality oflaterally spaced filter leaves secured fixedly to the element andconnected to supply the filtrate to the interior of the element fordischarge 40 from the casing, a longitudinally extending spray pipeextending through and slidable longitudinally in the ends of the casingand disposed in the top portion of the casing. directly adjacent to theinspection openings so that it is accessible from the outside of thecasing by Way of said openings, said pipe having one end thereofconnected to receive fluid under pressure and being provided with jetopenings for spraying the fluid against the sides of the filter leavesand adapted to be used in cleaning the filter to remove and loosen thecake formation from the sides of the filter leaves, screw meansassociated with one of the casing ends whereby the pipe may be slidlongitudinally so as to bring the jet openings into proper position withrespect to the leaves, means for driving the element so as to cause thefilter leaves to revolve through the material during normal use or thefilter and to bring successive portions of the cake formation into rangeof the jets of fluid under pressure from the spray-pipe during cleaningof the filter, and means associated with the bottom of the casing fordischarging the cake pieces from the casing.

WILLIAM L. CHAPMAN.

